Die-casting apparatus



Nov. 27, 1934. A. F. WALTZ DIE CASTING APPARATUS Filed April 20, 1951,LQLATTORNEY ZZZ 114 113 93 Patented Nov. 27, 1934 I UNITED STATESDIE-CASTING APPARATUS Anton F. Waltz,- Flushing, N. Y., 'assignor toEdgar N. Dollin, Malba, N. Y.

Application April 20, 1931, Serial No. 531,322

5 Claims.

. This invention relates to die-casting apparatus and more particularlyto the dies and means for cooperation therewith in effecting die-castingoperations.

Heretofore, in die-casting practice in general, various disadvantageousconditions have been encountered such, for example, as: the presence ofimpurities in the castings due to solution of iron from the apparatus asa result of the high temperature of the alloys required to enable themto be forced into the dies so as to fill the latter satisfactorily,failure to obtain the requisite solidity of castings, and the existenceof sprues of excessive size.

An important object of the present inventio is.to provide improved meansfor effecting diecasting operations. Another object is to providedie-casting means whereby the above mentioned and other disadvantageswill be obviated.

Further objects are to provide die-casting apparatus especially adaptedto cast metals or alloys at temperatures at which they fiow thickly,apparatus in which the pressure on the flowing metal is applied close tothe casting and there is minimum travel under pressure of the materialbeing cast, and apparatus adapted for supplying the casting material tothe casting cavities through one or a plurality of gates or lines ofsupply.

The apparatus of the present invention is adapted to operate on theusual metals and alloys adapted for die casting and upon alloys such asbrass, which could not be cast by use of the apparatus hitherto in use.The general die-casting industry here and abroad employs a submergedpressure chamber made of cast iron and pressure is generated either withcompressed air or gas or with a piston and cylinder. Brass can not becast practicallywith submerged pressure chambers, goosenecks in theordinary pneumatictype machine, because of the high temperaturerequired, about 2000 F. Brass can, however, be die-cast by thedisplacement means of the present invention, since it can be run in at alower temperature, that is, not above 1600 F., at which it issemi-plastic and will flow under high pressure such as a pressure offrom 2000 to 3000 pounds per square inch. At higher temperaturescommercial die life cannot be obtained but at not to exceed 1600" F.reasonable life and commercial application of the brassdie-castingprocess for brass and other alloys is feasible. The highpressure used also permits casting metals and alloys at lowertemperatures than before and results in less porosity and better finish.

Also in the apparatus of the present invention there is no, submergedchamber or goose-neck of cast iron thus substantially avoiding the usualdifficulties arising from the tendency of the iron to dissolve in thehot alloys. Solution of iron from the apparatus may be avoided by theuse of aluminum, but the aluminum is in many instances a harmfulconstituent. For example, aluminum is objectionable, in connection withzinc, from the standpoint of corrosion.

Aluminum in zinc or zinc-alloy castings causes intercrystallineoxidation or grain growth which makes the metal weak and brittleresulting in warpage and cracking. This action is induced by galvanicaction and hence is more rapid in hot moist climates or in the presenceof moisture or saline solutions. Steam causes rapid failure and is usedfor artificial aging tests. Most commercial zincs contain lead andcadmium which are especially harmful in the presence of aluminum and inconsequence the die-casting industry to produce castings which will beusable, must use 99.99 pure zinc, whereas with our process byeliminating aluminum lower grades of zinc can be used.

When the aluminum is eliminated a wide range of superior -zinc alloyscan be cast and this is made possible by the elimination of thesubmerged pressure chamber and consequent complications'caused by theabsorption of iron.

The absorption of iron is also harmful in casting aluminum alloys as itmakes them corrosive, brittle and weak. Much greater resistance tocorrosion and higher physical characteristics can be produced in thealuminum series by the elimination of iron and employment of highpressure 0 and quick chilling.

Other features and advantages will appear upon consideration of thefollowing description and of the drawing in which:

Fig. l is an elevation of one form of apparatus embodying the invention;and

Fig. 2 is a top plan view of the structure shown in Fig. 1.

Referring to the drawing in detail, 75 and '76 designate end frames ofwhich theframe 75 may be referred to as the front frame and '76 as therear frame. The top of the rear frame 76 is connected by a guide member77 with the front frame 75 at the corresponding level. As here showntheguiding member '77 is in the form of a bolt which has at its frontend a reduced portion 78 passing through a corresponding bore, in theframe '75 and at its rear end a correspond ing reduced rear portion 79which passes through a corresponding bore in the upper end of the rearframe 76.

The shoulder at the end of the reduced portion 78 may not rest directlyagainst the rear side of the front frame 75 but, as here shown, a washer80 is interposed between the shoulder and the frame. At the other sideof the frame 75 the reduced end 78 is provided with a suitable screwthread to cooperate with a nut 81 which may engage the front face offront frame '75 but preferably is separated therefrom by a Washer 80similar to that used at the other or rear face of the front frame. Theupper end of the front frame 75 is also connected by means of a guide82, preferably of the same general form as bolt 77,

with a member 83 mounted at its lower end on the reduced portion 79 ofthe bolt 77, which reduced portion extends through the top of the rearframe 76. The shoulder formed at one end of the reduced portion 79 ofthe bolt 77 may engage the front face of the member 83, the rear end ofthe reduced portion '79 being threaded to receive a nut 85 which mayengage the rear face of the frame '76 or may be separated therefrom bymeans of a washer 86. To hold the member 83 from swinging downwardlyaround the reduced portion '79 of the bolt 77, it is provided with asuitable bore registering with a similar bore in the frame 76 so thatthe member 83 and the frame 76 may conveniently be fastened together bysuitable means such as a screw or bolt 89.

The member 83 serves as a holder for a stationary die which is securedthereto in any suitable manner. Cooperating with the fixed die 90 is amovable die 91 supported to move horizontally toward and from the fixeddie 90 by means including an ejector box 92 connecting it with a movabledie-holder 93 slidably mounted at the bottom and top on the bolts orguides 77 and 82, respectively.

Actuation of the movable die support or holder 93 may conveniently beeffected by means of an arm 94 suitably connected, as by means of a key95, with a shaft 96, rotatably mounted in a member 97, which in turn ismounted on the bolts 77 and 82. To enable adjustment thereof toward andfrom the frame 75 for purposes to be brought out hereinafter, the member97 is secured by means of nuts 98 co-operating with the screw threadedsurfaces of the guide bolts 77 and 82 and engaging member 97 on oppositesides. Mounted on the shaft 96 at opposite sides of the member 97 aretoggle arms 99 which at their other ends are connected by pivots 100with links 101 pivoted in turn to the movable die support 93 by pivots102. Obviously, counter-clockwise swinging of the arm 94 to its leftposition, as viewed in Fig. 1, will straighten the toggle comprising thearms 99 and 101, and swinging of the arm 94 in the clockwise directionwill release the toggle. Although the movement of the movable die-holder93 might be effected by a single toggle such as that just described, itis desirable to actuate the holder at both top and bottomsimultaneously. Accordingly the toggle just described is connected withthe member 97 and the die-holder 93 at points which are nearly at thesame level as the bolt 82, and similar toggle member are provided atsubstantially the level of the bolt 77, the arms 99 of these lowertoggles being connected with the member 97 in a suitable manner, as by asuitable pivot or pivots 103 instead of a shaft corresponding to theshaft 96.

To effect corresponding and simultaneous movements of the upper andlower toggles on each side, provision is made of suitable means, such asa link 104, having its upper end pivoted at 105 to a lug 106 extendingdownwardly from the upper toggle arm 99 and having its lower endconnected by a pivot 107 with a'corresponding lug 106 projectingdownwardly from the corresponding lowe toggle arm 99. Obviously,adjustment of the member 97 toward. or from the frame '75 will vary thetoggle action.

It will be evident that upon swinging the arm 94 in a counter-clockwisedirection to separate the dies the link 104 will tend to engage .thelower pivot 103. Therefore, to permit movable die 91 to be withdrawn toa suitable distance from the fixed die member 90, each link 104 may beso shaped as to provide a recess at its front side at the point wherethe link would engage the pivot 103. As illustrated in Fig. 1 the effectdesired is produced by using a bent link 104.

In this form of the apparatus the stationary and movable die members 90and 91 are provided with suitable co-operating die-casting cavities 109and also with a well 110 arranged vertically, 100 half thereof being inone die and half in the other. Metal at a suitable temperature andcondition is introduced into the well 110 and is displaced by means of aplunger 111 so as to enter the casting cavities 108 and 109 after themova- 105 ble die member has been pressed against the fixed die member.

The metal displaced from the well 110 is forced upwardly through achannel 112 at the side of the well 110 and then into the castingcavities. The 110 plunger 111 should be close to the upper end of thewell before it is actuated, and consequently any substantial separationof the plunger from the die or dies should be avoided, thus rendering itdifiicult to supply hot metal to the well 110 by means of a ladle.However, as indicated, the dies 90 and 91 may be provided at their uppersurfaces with a receiving cavity 113 half in each of the dies andconnected with the well 110 by means of a passage 114*which is also halfin one die and half in the other. In this connection it should be saidthat the lower end of the passage 114 should be at a higher level thanthe point of communication between the upright channel and the castingcavities.

The plunger 111 may be operated by suitable means including, forexample, acylinder 115 into which the plunger extends, a piston 116fastened to the upper end of the plunger and pipes 117 and 118connecting, respectively, the upper and lower ends of the cylinder withsuitable means for controlling the fluid pressure at the upper and lowersides of the piston to raise and lower the plunger as desired. In thisconnection, it may be noted that due to the mounting of the die supportson the bolts 77 and 82, one of which is above the other, the cylinderand plunger are located at one side of the plane of the guide bolts.

The cylinder 115 may be mounted in any suitable manner. For example asillustrated, the cylinder may be mounted on a plate or block 119 securedto the upper edge of the member 83 by suitable means such as screws 120.No provision is made for a fixed support for the plate 119 at the sideof the cylinder toward the frame 75, but the movable die-holder 93 isutilized for supporting purposes as by providing the plate 119 with arecess or socket 121 to receive a projection or pin 122 on a block 123securedto the movable die- 5 holder 93 in a suitable manner as, forexample by a screw 124.

The operation of this form of the apparatus is substantially as follows:Assuming that the operating arm 94 is in its right hand (Fig. 1) orforward position, the movable die 91 is separated from the stationarydie 90 as it would be just after removing a casting. The arm 94 is thenswung counter-clockwise to straighten the toggles and bring the movabledie 91 into cooperative engagement with the fixed die 90 as well as movethe projection or pin 122, carried by the movable holder 93, into therecess or socket 121 in the plate 119 carrying the cylinder 115.

Hot metal in condition to flow is then poured into the receiving cavity113 and flows through the passage 114 into the well 110.- Fluid underpressure is then admitted to the upper part of the cylinder 115 to forcedown the piston 116 and consequently drive the plunger down into thewell 110. This movement of the plunger displaces the metal upwardlythrough the channel 112 and into the casting cavities109. The pressurein the upper part of the cylinder is then relieved and fluid underpressure is supplied to the lower end thereof to raise the piston andwithdraw the plunger from the well 110. Then the operating arm 94 isswung clockwise to break the toggles and withdraw the movable die withthe casting, and the casting is separated from the movable die bysuitable ejecting means in the ejector box 92. The machine is then readyfor another die casting operation.

It will be seen that machines constructed in accordance with the presentinvention have many advantages over machines heretofore in general use.For example metals or alloys can be used at temperatures at which theyflow thickly, thus enabling die casting to be effected at lowertemperatures than usual and the use of metals having higher meltingpoints. Due to the lower temperatures at which die casting can be doneby use of the present invention and also due to the short distancesthrough which the metal travels to the casting cavities, impuritiesincluding iron in solution are to a great extent eliminated. Similarlyaluminum is no longer a necessary constituent of zinc alloys or viceversa, castings may be made more solid because of the higher pressurepossible and also the comparatively low temperatures. Other advantagesarise from the application of pressure close to the casting and theshort or minimum travel required under pressure.

The present invention also adapts itself to the use of a plurality ofsources of metal supply to the casting as required and to the making ofa plurality of castings at one operation. The sizes of the wells may bemade to suit the size of the castings and the wells may be replaceable.

Also the general arrangement assists in temperature control. It will ofcourse be understood that temperature control of parts of die-castingapparatus has heretofore been obtained by ducts through which liquidis'circulated.

It should be understood that various changes may be made in theconstruction and arrangement of parts and that certain features may beused with others without departing from the true spirit and scope of theinvention.

Having thus described my invention, I

claim:- v

1. In die-casting apparatus, two die members with vertical inner facesprovided with casting cavities, a vertical well half in one die memberand half in the other and a channel at the side of said wellcommunicating with the upper part of the casting cavities; a plunger tofit insaid well; means to depress said plunger and displace hot metal insaid well to force it into the casting cavities; and means forseparating said die members to remove a casting and for forcing themtogether preparatory to forming another diecasting.

2. In die-casting apparatus, two die members with vertical inner facesprovided with casting cavities, a vertical well half in one die memberand half in the other and a channel, at the side of said wellcommunicating with the upper part of the casting cavities; a plunger tofit in said well; means to depress said plunger and displace hot metalin said well and force it into the casting cavities; and means forseparating said die members to remove a casting and for forcing themtogether preparatory to forming another die-casting and means forsupplying metal to said well including a chamber in the upper part ofone of said die members and a passage leading downwardly to said well.

3. In die-casting apparatus, two die members with vertical inner facesprovided with casting cavities, a vertical well half in one die memberand half in the other and a,channel at the sideof said wellcommunicating with the casting cavities; a plunger fitting said well;means to depress said plunger and displace hot metal in said well andforce it into the casting cavities;

means for separating said die members to remove a casting and forforcing them together preparatory to forming another casting; and meansto supply metal to said well including a receiving chamber half in onedie member and half in the other, and a passage leading from saidchamber to said well.

4. In die-casting apparatus, two die members having cooperating sidesprovided with casting cavities, a well half in' one die member and. halfin the other, an inlet to direct hot metal to said well and a channel atthe side of said well communicating with the casting cavities; a plungerto fit in said well; means to depress said plunger and by displacementof hot metal in said well force it into the casting cavities, and meansfor separating said die members to remove a casting and for pressingthem together preparatory to supplying hot metal to said well andforming another die-casting.

5. In die-casting apparatus, two die members having inner faces providedwith casting cavities, a well half in one die member and half in theother, an inlet to direct hot metal to said well and a channel at theside of said well communicating above the bottom of said'well with thecasting cavities; a plunger of a cross section to fit said well; meansto operate said plunger and by displacement from the well force themetal into the casting cavities; and means for separating said diemembers for removal of a casting and for forcing them togetherpreparatory to supplying hot metal to said well.

ANTON F. WAL'IZ.

